The primary goal of this project is to develop a robust treatment system to efficiently remove organic constituents from produced water in a cost-effective manner. The process consists of a surfactant modified zeolite (SMZ) system developed as part of DOE Contract No. DE-AC26-99BC15221, "Treatment of Produced Oil and Gas waters with Surfactant-Modified Zeolite," combined with a vapor-phase bioreactor (VPB) developed as part of this research.
University of Texas at Austin
Department of Civil, Architectural, & Environmental Engineering
Department of Earth & Environmental Science
New Mexico Institute of Mining and Technology
The major accomplishment of this work has been the development of a treatment process for BTEX (benzene, toluene, ethylbenzene, and xylene) removal from produced water that can yield complete destruction of the BTEX compounds. SMZ adsorption followed by regeneration has been demonstrated over multiple cycles without loss of adsorption capacity. The vapor phase bioreactor is capable of treating the offgas produced during regeneration and operating over the intermittent cycles of operation that will be required in small-scale systems.
Reuse of produced water will greatly impact production costs in the oil and gas industry. Estimated produced-water disposal costs per barrel range from $0.50 to $4.00, based on such factors as transportation, treatment, and reinjection costs. In the United States, the average production of produced water is 10 barrels of water for each barrel of oil. The BTEX/VPB technology is being designed as a robust system to facilitate treatment at water disposal sites, thereby reducing production costs and providing beneficial reuse of the water.
SMZ is an innovative filtration/sorption medium that has been shown to remove contaminants such as BTEX from produced waters. Cost-effective operation of an SMZ requires way to regenerate the SMZ onsite. Air-sparging has proven effective for regeneration; however, this process generates a moist air stream contaminated with relatively low concentrations of volatile organic compounds (VOCs), including BTEX. Because these VOCs are biodegradable and present in dilute concentrations, a vapor-phase bioreactor can be used to destroy the pollutants generated in the SMZ regeneration step. In VPBs, microorganisms growing on a fixed packing media are used to biodegrade organic pollutants found in the waste gas stream being treated. Products of the biodegradation include carbon dioxide, water, and new biomass. Once the VPB is developed, a series of laboratory and field-scale experiments are required to optimize the SMZ/VPB combination specifically for produced water. Furthermore, evaluation and design of the regeneration method for the SMZ process has not been fully addressed in previous research but will be a key component in the success of this project.
In this project, researchers:
Researchers completed construction of the building and reactors for the field-scale evaluation of the SMZ/VPB system in August 2005. A change in location from a site in Wyoming to the McGrath location was made to provide the necessary "pilot" level data for a larger-scale, long-term, follow-on study that was funded based on the results of this project. A no-cost extension request has been submitted to allow researchers to complete the field-scale evaluation and summarize the results of the testing
$241,176 (24% of total)
Other Government Organizations Involved
Los Alamos National Laboratory
Ranck, J.M., Bowman, R.S., Weeber, J.L., Katz, L.E., and Sullivan, E.J., 2005, BTEX removal from produced water using surfactant-modified zeolite. J. Environ. Eng.131:434-442.